Unlock instant, AI-driven research and patent intelligence for your innovation.

Methods for forming dielectric films and related film capacitors

a dielectric film and film capacitor technology, applied in the direction of wound capacitors, stacked capacitors, fixed capacitor details, etc., can solve the problems of poor thermal stability, dielectric properties, and the presence of residual solvents in the film, and achieve the effect of improving thermal stability and dielectric properties

Inactive Publication Date: 2017-06-22
GENERAL ELECTRIC CO
View PDF4 Cites 2 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

This patent describes a method for making a thin film of dielectric material that can be stretched in both directions to make a bi-axially stretched film. The material is heated with infrared radiation while it is being stretched and the resulting film has a thickness of less than 5 microns. The method uses a polyetherimide film that is melt-extruded and then stretched along both the length and width directions to create a highly uniform film that is suitable for use in capacitor applications. The technical effect of this method is the ability to make a thin, flexible film that can be easily and uniformly stretched in both directions.

Problems solved by technology

However, polypropylene-based film capacitors may have challenges in high-temperature industrial applications because of polypropylene's inherent temperature limitations.
However, conventional methods for forming thin polymer films, for example, solvent-based methods may have several issues including the presence of residual solvent in the film, shrinkage, poor thermal stability, and dielectric properties.
However, forming thin films of amorphous polymers may be challenging because of the lack of appropriate methods and processing conditions to achieve the desired thickness (less than 5 microns), uniformity and quality.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Methods for forming dielectric films and related film capacitors
  • Methods for forming dielectric films and related film capacitors
  • Methods for forming dielectric films and related film capacitors

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0051]A uni-axially stretched polyetherimide (PEI) film of nominal thickness 6 microns (Ultem™) was provided. The PEI film was about 19 inches wide and had surface imperfections (e.g., surface instabilities of the tin-canning type). These surface instabilities might have prevented this roll of PEI film from being metallized to finally use the metallized PEI film to form film capacitors.

[0052]To carry out TDO stretching of the PEI film, a web roll of the PEI film was transported to an entrance of an infra-red transverse direction orientation (IRTDO) system by rollers. At the entrance, the edges of the PEI film were gripped by the tenter clips of a tenter frame. The PEI film entering the tenter clips was at about room temperature. After gripping the PEI film, the tenter clips were moved in relatively straight parallel rails of tenter frame into a first section 22 (referring to FIG. 4) where the temperature of the PEI film was increased to a deformation temperature of PEI, with the hel...

examples 2-7

[0056]Six polyetherimide (PEI) films (Ultem™) were provided. The PEI films had surface imperfections (e.g., surface instabilities of tin-canning type). Details of the wrinkled PEI films and the method used to process them, for example web-roll lengths, widths, thicknesses, unwind tension are provided in Table 1. The PEI films were processed using the same method as described above in Example 1 to form bi-axially stretched PEI films. Similar measurement processes were performed for measuring average thicknesses and breakdown strengths of bi-axially stretched PEI films as discussed in Example 1.

[0057]Table 1 shows the processing conditions and parameters (e.g., IR heaters' temperatures, tenter speeds, rail separations, stretch ratios, web rewind tensions, web exit widths, web exit thicknesses) used while processing the PEI films in Examples 2-7. Table 1 further shows average thicknesses and average breakdown strengths measured at two different regions (region 1 and region 2) of result...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

PropertyMeasurementUnit
Temperatureaaaaaaaaaa
Temperatureaaaaaaaaaa
Thicknessaaaaaaaaaa
Login to View More

Abstract

A method for forming a bi-axially stretched dielectric film having a thickness less than 5 microns is presented. The method includes stretching a dielectric material along a transverse direction to form the bi-axially stretched dielectric film having a thickness less than 5 microns. The dielectric material is heated using infrared radiation during at least a duration of the stretching step. The dielectric material includes a substantially amorphous polymer having a glass transition temperature greater than 140 degrees Celsius.

Description

BACKGROUND[0001]The disclosure relates generally to methods for forming dielectric films. More particularly, the disclosure relates to methods for forming bi-axially stretched dielectric films of amorphous polymers.[0002]Over the last decade, significant improvements in capacitor reliability have been achieved through a combination of advanced manufacturing techniques and new materials. Enhanced performance has been obtained particularly in so-called film capacitors, such as metallized film capacitors.[0003]Compared to other types of film capacitors, metallized film capacitors may provide certain advantages such as size, simplicity, and cost of manufacturing, and hence have been widely used in the power electronics industry. Typically, metallized film capacitors include two metal electrodes separated by a polymer film. An example of the commonly used polymer film includes polypropylene. However, polypropylene-based film capacitors may have challenges in high-temperature industrial a...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
IPC IPC(8): B29C55/14B29C55/04B29C55/00B29C55/16H01G4/33H01G4/06
CPCB29C55/146H01G4/33H01G4/06B29C55/005B29L2031/34B29C55/04B29K2079/085B29L2007/008B29C55/16B29C55/12H01G4/32H01G4/015H01G4/18Y02T10/70
Inventor SILVI, NORBERTOFLANAGAN, KEVIN WARNERTAN, DANIEL QISULLIVAN, JEFFREY S.
Owner GENERAL ELECTRIC CO